An Ad Hoc Network Load Balancing Energy- Efficient Multipath Routing Protocol

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1 246 JOURNA OF SOFTWAR, VO. 9, NO. 1, JANUARY 2014 An Ad Hoc Network oad alancng nergy- ffcent Multpath Routng Protocol De-jn Kong Shanx Fnance and Taxaton College, Tayuan, Chna mal: Xao-lng Yao Shanx Fnance and Taxaton College, Tayuan, Chna Abstract Multpath routng protocol establshes multple transmsson paths between source node and destnaton node, whch can not only transmt data n parallel, but also one as man path and others as backup paths. The paper proposed a multpath routng protocol P_ wth power controllng and load balancng based on. In order to mplement load balancng and prolong network lfetme, t allocates traffc bandwdth based on node remanng power and load status along the path. Approprate power s used to transmt data packets. As Ad hoc network s complcated and changeable, the proposed protocol conducts perodcal routng mantenance to adjust bandwdth allocaton of traffc n tme. Smulaton experment results show that the mproved P_ protocol acheves better performance n the aspects of load balancng and average node lfetme. Index Terms multpath routng, Ad hoc, power controllng, load balancng I. INTRODUCTION Ad hoc has not wreless nfrastructure, but runs n the manner of wreless mult-hop relay. For ts hgh flexblty, moblty, self-organzatons as well as access anytme and anywhere, Ad hoc has been wdely used n varous mltary and cvlan felds of emergency relef, smart communcatons, envronmental montorng and etc. Ad hoc routng protocol has several classfcaton methods. Accordng to transmsson path number between source node and destnaton node, t can be dvded nto sngle-path routng protocol and mult-path routng protocol. Sngle-path routng protocol means there s only one path between source and snk. Common sngle-path routng protocols nclude [1], DSR [2], OSR [3] and etc. The mult-path routng protocol establshes multple transmsson paths from source to destnaton, whch can not only be sued for data transmsson, but also one as man path and others as backup. The paper addressed to former stuaton. Typcal mult-path routng protocols nclude [4], SMR [5], MP-DSR [6], TP [7] and etc. Among them, s a knd of on-demand mult-path routng protocol expanded from, the man dea of whch s to buld multple ndependent paths between source node and destnaton node to mplement parallel transmsson of data. The paper brngs out a mult-path routng protocol wth power controllng and load balancng P_. Smlar as, P_ protocol should frstly establsh multple ndependent paths. Secondly, n order to balance node load and power as possble, t should allocate traffc among paths to acheve optmal traffc transmsson mode. Fnally, P_AODMV protocol needs to control sngle hop transmsson power to save precous energy. Among them, ndependence of mult-path s the frst problem to be solved, whch s also the premse to execute other traffc allocaton algorthms or QoS resource reservaton algorthms [8]. The paper s organzed as follows. Secton 2 gves establsh method of P_ ndependent path. Secton 3 ntroduces mplement strategy of protocol. Secton 4 desgns routng process of P_ n detal. Secton 5 performs smulaton experments and result analyss. Secton 6 concludes our work. Ⅱ. STAISHMNT OF P_ INDPNDNT PATHS The ndependence of path s very mportant to multpath routng. Stronger s ndependence of path, the network resource utlzaton can be more adequate and the node congeston probablty s lower. In the mult-path routng, ndependent paths can be dvded nto node dsjont paths and lnk dsjont paths [6]. Node dsjont path means there s not two same nodes n these paths. nk dsjont path refers to there s not same lnk along two paths. The paths not belong to these above two are un-dsjont. Generally, the number of node dsjont paths s less than that of lnk dsjont. However, the ndependence of node dsjont s better than that of lnk dsjont. Therefore, we try to establsh node dsjont path. Varous dsjont paths are shown from Fg. 1 to Fg. 3. Where, S s source node and D as the destnaton. The path SACD and SFG n Fg. 1 are node dsjont paths. The SACD and SFD n Fg. 2 are lnk dsjont paths. The SAD and SCD n Fg. 3 are un-dsjont paths. In the Ad hoc, f un-dsjont multpath are used for data transmsson, the nodes or lnks been commonly used by 2014 ACADMY PUISHR do: /jsw

2 JOURNA OF SOFTWAR, VO. 9, NO. 1, JANUARY paths can easly become a bottleneck, thus effect of traffc dvson cannot be acheved. If the common nodes faled, multple paths wll smultaneously breakng. S A C F Fgure 1. Node dsjont path S A C D F Fgure 2. nk dsjont path S A D C Fgure 3. Un-dsjont path In order to effectvely establsh multple node dsjont paths and avod consumng too much network resources, P_ ntroduce the followng theorem [9, 10]. Theorem 1: The path from source node S to destnaton D along all dfferent adjacent nodes of S s node dsjont. III. IMPMNTATION STRATGIS A. P_ Flow Dstrbuton Manner To mplement traffc balancng, routng protocol should perform traffc allocaton on bult multple paths. The traffc strategy n the paper s as followng. In the routng searchng, save bandwdth along the path and remanng power to routng reply packet. Source node computes traffc allocaton of each path based on these two parameters. Here we wll ntroduce computaton method of bandwdth and power as well as traffc allocaton strategy below. The dle tme of node n the channel s an mportant factor to measure effectve bandwdth, whch s comprehensvely determned by traffc of node and ts neghbors. Therefore, the effectve bandwdth can be computed as follows: () = T / T (1) avalable dle nt erval Where, avalable () s avalable bandwdth of node ; s mum transmsson bandwdth of node; T nterval s statstcs nterval; T dle s dle tme n channel statstcs. We also use lnear decreasng model to smoothen changes of bandwdth parameters: () = (1 α) ( 1) + α () (2) real real avalable Where, real () s real effectve bandwdth at tme ; real (-1) s the real bandwdth at tme -1; avalable () s D effectve bandwdth at tme accordng to (1); α s the adjustable weght n the nterval (0,1). Remanng power of nodes along the path has mportant effect on path lfelong. The computaton of energy bottleneck of path nodes should frstly obtan resdual energy of each node, whch can be drectly obtaned by checkng battery of nodes. As numercal level of avalable bandwdth and energy s magntude, the paper unfes metrc of resdual bandwdth and energy before path relablty computaton. Avalable bandwdth and energy were dvded nto eght dfferent levels. The hgher the level, the avalable resources are more abundant. The level of avalable bandwdth and energy are computed as follows: = floor(_ ( ) / ) (3) real = floor(_ ( ) / ) (4) real Where, and are level of node bandwdth and resdual energy; real () s resdual energy of node at tme ; s ntal node energy; _ s set 8; floor means floor functon been used. Assume the path from S to D s ( SS, 1, S2,, S,, Sj, D). The and are used to represent avalable and resdual energy of node S. The bandwdth _mn and energy bottleneck _mn can be obtaned: _mn = mn(, = 1, 2,, j) (5) _mn = mn(, = 1, 2,, j) (6) Assume source node S establshed k paths to destnaton node, relablty of the -th path s R = ( )/ hopcount. (7) _mn _mn Where, hopcount s hop number of the path. Allocate traffc on these k paths accordng to relablty, bandwdth of the -th path s: k = R / Rj (8) j= 1 It s worth notng dsorder of packets of mult-path n TCP flow transmsson [8]. We use dfferent method to process dfferent traffc. If some node needs to transmt UDP, t wll be dvded to be transmtted along dfferent paths, others beng backup.. P_ Transmt Power Control Ad hoc s a restrcted network. Once power energy of node s exhausted, t wll drectly affect mplementaton of network functons. In the case of no power-aware, packet s transmtted wth mum power. If power control s added n MAC and each hop be transted wth approprate power, node energy consumpton can be nevtably reduced. Meanwhle, as data packet transmsson range beng smaller, nterference among nodes also nevtable reduces. The messages n MAC can be broadly dvded nto broadcast massage and uncast message. P_ 2014 ACADMY PUISHR

3 248 JOURNA OF SOFTWAR, VO. 9, NO. 1, JANUARY 2014 protocol transmts broadcast message wth mum power and uncast message wth approprate power. For example, f node A and are neghbor nodes and A needs to transmt to, A sends RTS wth mum power P. After receved RTS from A, t wll send CTS wth P. When node A receved CTS, t computes data transmsson power P data_send accordng to recevng power P receve and transmttng power P. P P = P c (9) data _ send threshold P r eceve Where, P threshold s the necessary power for correctly recevng; c s a constant to prevent too small power to receve data, whch s generally set c>1. As P data_send s smaller than P, t can save data transmttng power by power controllng. IV. P_ ROUTING PROCSS A. Routng Dscovery In order to mplement node dsjont path and traffc controllng, we should frstly expand format of routng control packet and routng table package of protocol. Frstly, expand format of RRQ. Add next hop node address SN feld of source node n RRQ to record frst neghbor node address of source node. At the same tme, add bandwdth W feld and resdual energy fled to record bottleneck of forward routng. Secondly, expand routng table. Add source address SA, bandwdth W, resdual energy tems n routng table. Thrdly, destnaton node mantan node neghbor lst lst(sn) to record source node address SA and neghbor node address SN n RRQ. Add felds of W and n RRP to record reverse routng bottleneck. RRQ packet processng When node s needs to communcate but there s not avalable routng, t ntate routng dscovery process to broadcast routng request RRQ to all neghbors. The felds of W and n RRQ packet are ntaled values of source node. After ntermedate node receved RRQ packets, t determnes whether receved repeated packet wth same source address, destnaton address and request ID n source neghbor address feld SN n tme of path_traversal_tme. After all ntermedate nodes receved RRQ for frst tme, compare bandwdth and resdual energy of ths node wth W and n RRQ. If current value s smaller than that n packet, the node may become bottleneck. Update value of current node to RRQ packet. When ntermedate node receved request packet wth same destnaton address from dfferent source nodes, establsh dfferent routng tems for dfferent source nodes. Other routng update mechansm and forward mechansm of ntermedate node are same as that of. When destnaton node receved RRQ, t wll extract source address SA and neghbor address SN and determne whether SA and SN from packet n lst(sn). If so, drectly dscard the packet. Otherwse, add (SA, SN) nto lst(sn) and establsh reverse path wth source node. Send routng reply packet RRP to source node. As to same source node, P_ protocol at most establshes three paths. RRP packet processng The W and felds n RRP are used to record bottlenecks from current node to destnaton node, whch s dfferent from bottleneck to destnaton node. Therefore, the W and felds n RRP are ntalzed as value of destnaton node. The processng method of ntermedate node after receved RRP packet s substantally same as that of RRQ, namely compare bandwdth and resdual energy of ths node wth W and n RRP. If value of ths node s smaller than that n packet, update node value nto packet. Otherwse, do not update. All nodes receved RRP should establsh forward path for source node and record bandwdth and energy bottleneck to destnaton node. Then, t forwards RRP. After source node receved multple RRP, t extracts W and felds n order to establsh routng tems to destnaton node.. Routng Mantenance Process Ad hoc network has complex characterstcs. After source node traffc transmsson, nodes along transmsson paths may access new traffc or shft to regon wth poor bandwdth resources. andwdth and energy bottleneck of each path wll nevtable change as tme. If the source node stll allocate traffc accordng to stuaton n routng establshment, t s obvously very unreasonable. Therefore, P_ protocol added perodc routng mantenance on paths to fnd network congeston or node energy change n tme, so as to acheve bandwdth allocaton of traffc adjustment. P_ adds perodc routng mantenance process. In the routng dscovery phase, destnaton node bulds a tmer once recevng frst RRQ of source node. The tmer s responsble for perodc routng mantenance to ths source node. We call t as routng mantenance tmer. When the tmer expres, f ths path stll actve recently, destnaton node frstly add ID of ths node and then send RRP along multple paths to source nodes. After source node receved RRP, t updates W and nformaton of ths packet to routng table. In case of source node sendng packets to destnaton node n next tme, f allocates traffc n accordance wth new parameters. We uses destnaton node to mantan paths. The beneft s that overhead of destnaton node sendng path mantenance nformaton to source node drectly s less than source node send to destnaton and then return. However, t should ensure the path from source to destnaton s same as that from destnaton to source. Otherwse, the obtaned bandwdth and bottleneck s not real value along transmsson path. The references [11-13] have proved that the establshed path wth theorem 1 can meet above condtons. The processng on path falure of P_ s smlar to that of. After ntermedate node fnd path falure to destnaton node, t frstly send path falure message to source node and delete reverse paths to source 2014 ACADMY PUISHR

4 JOURNA OF SOFTWAR, VO. 9, NO. 1, JANUARY node. If upper hop of some ntermedate node to destnaton node, t send path falure message to source node and delete reverse paths to destnaton node. After source node and destnaton node along ths path receved message, delete path n routng table respectvely. Dfferent from, f there s avalable path to destnaton node n the routng table of source node, P_ does not perform route recovery operaton tll there s no avalable path from source to destnaton node. V.SIMUATION XPRIMNT AND RSUT ANAYSIS A. Smulaton Scenaro We desgned smulaton experment on P_ protocol wth NS-2.33 platform under nux operaton system. In the smulaton, the terran was set plane network of m m; node number 20; MAC protocol as I DCF; sgnal propagaton manner as dual-dameter ground reflecton model; node mum communcaton range as 250m; channel bandwdth 2Mbps. The ntal energy of all nodes was set same value. Data packet length s 512yte and smulaton tme as s. The constant UDP bt stream was used to smulate real-tme traffc and 8 connectons were ntated randomly. We select the followng performance parameters to evaluate algorthm. (1) Node number of energy exhausted. (2) Average lfespan of frst half dead nodes. (3) Control overhead. In order to valdate P_ performance, the paper smulated protocol and protocol wth same movng speed under same condtons. The protocol n experment s transmtted n parallel wth multple paths and at most three decle paths been establshed. Compared wth P_, the smulated protocol has not power controllng and traffc allocaton.. Result Analyss The relaton between dead node number and elapsed tme reflects unformty of the energy consumpton of each node. If the mage s steeper, t ndcates that lfe cycle of each node n the network has greater dfference and energy consumpton more uneven. On the contrary, f the mage s gentler, each node survval smaller the dfference between the consumpton of energy s more unform, network because the node energy s exhausted and the probablty of splttng the smaller. At the same tme, snce the node of the energy consumpton and the node load substantally proportonal, the node energy consumpton also reflects the degree of load balancng n the network, the node energy consumpton s more unform, and the network load s more balanced. Fg. 4, Fg. 5 and Fg. 6 show relatons between dead node number and elapsed tme at movng speed of 0m/s, 2m/s and 5m/s. After comparson, we can know that the curves of are relatvely steep. The curve of s slghtly better than that of, they are also very steep. It suggests that node energy consumpton of and has large dfference. The curve of P_ protocol s also on the top of that of and. Meanwhle, the P_ s relatvely smooth, whch ndcates node energy consumpton of P_ s more unform than and. We can also know from these three mages that P_ protocol can reach energy and load evenly at dfferent movng speed. lapsed tme/s 450 P_ Fgure 4. Relatonshp between dead node and elapsed tme at 0m/s lapsed tme/s 450 P_ Fgure 5. Relatonshp between dead node and elapsed tme at 2m/s lapsed tme/s P_ Fgure 6. Relatonshp between dead node and elapsed tme at 5m/s Fg. 7 shows average lfe of frst 10 dead nodes from experment n Fg. 4 to Fg. 6. Under dfferent movng speeds, average lfe of frst half dead nodes n P_ protocol delay 2%-5% than that of and, whle P_ prolongs 12%- 18% than, whch means P_ can also acheves energy savng wth power controllng ACADMY PUISHR

5 250 JOURNA OF SOFTWAR, VO. 9, NO. 1, JANUARY 2014 Average dead tme/s P_ Movng speed/m/s Fgure 7. Average lfe of frst 10 dead nodes Fg. 8 shows comparson of network overhead. As P_ adds bandwdth and energy parameters n routng packet as well as perodc network mantenance mechansm, the overhead of P_ s slghtly ncreased than, but stll less than that of. Seen from performance of energy and load balancng, the ncreased overhead s worthy. Routng overhead/% P_ Movng speed/m/s Fgure 8. Network overhead comparson VI.CONCUSION The paper mproved on protocol to brng out a mult-path routng protocol P_ wth power controllng and load balancng. It establshed multple node dsjont paths between source node and destnaton node to mplement parallel data transmsson. The protocol allocates bandwdth accordng to resdual energy and load bottleneck so that path load and resdual energy balanced roughly, so as to reduce probablty of falure caused by node energy exhausted and prolong overall connectvty. As Ad hoc s complex and volatle, the establshed path may shft to regon wth poor bandwdth resources and node bottleneck may change, P_ adds perodc routng mantenance to adjust bandwdth allocaton n real-tme. In addton, P_ protocol transmts data packets wth approprate energy n case of data transmsson to avod usng mum power and save node energy. Smulaton experment wth NS-2 shows that the mproved P_ protocol better network performance n aspects of load balancng and average node lfespan. In the next workng, we wll further analyze varous traffc allocaton algorthms to provde theoretcal bass for further mprovement. RFRNCS [1] Perkns C.., Royer. M., Ad-hoc on-demand dstance vector routng, Proceedngs of 1999 Second I Workshop on Moble Computng Systems and Applcatons (WMCSA 99), Feb 25-26, pp , [2] e Wang, an-fang Zhang, Yan-ta Shu, Mao Dong, Multpath source routng n wreless ad hoc networks, Proceedngs of 2000 Canadan Conference on lectrcal and Computer ngneerng, pp , [3] Jacquet P., Muhlethaler P., Clausen T., aout A., Qayyum A., Vennot., Optmzed lnk state routng protocol for ad hoc networks, Proceedngs of 2001 I Mult Topc Conference on Technology for the 2st Century (INMIC), pp.62-68, [4] Mateen W., Raza S., Uzm Z. A., aqa S., Adaptve mult-path on-demand routng n moble ad hoc networks, Proceedngs of ghth I Internatonal Symposum on Object-Orented Real-Tme Dstrbuted Computng, pp , [5] ee S. J., Gerla M., Splt multpath routng wth mally dsjont paths n ad hoc networks, Proceedngs of I Internatonal Conference on Communcatons (ICC 2001), pp , [6] Rashda Hashm, Qassm Nasr, Saad Harous, Adaptve Mult-path QoS Aware Dynamc Source Routng Protocol for Moble Ad-Hoc Network, Proceedngs of 2006 Innovatons n Informaton Technology, pp. 1-5, [7] eung R., J-le u, Poon., Chan A..C., ao-chun, MP-DSR: a QoS-aware mult-path dynamc source routng protocol for wreless ad-hoc networks, Proceedngs of 26th Annual I Conference on ocal Computer Networks, pp , [8] Shgang Chen, Nahrstedt K., Dstrbuted qualty-ofservce routng n ad hoc networks, I Journal on Selected Areas n Communcatons, vol.17, no.8, pp , [9] Cheng-yong u, a-yuan, Yang Xang, Research of Mult-Path Routng Protocol ased on Parallel Ant Colony Algorthm Optmzaton n Moble Ad Hoc Networks, Proceedngs of Ffth Internatonal Conference on Informaton Technology: New Generatons (ITNG 2008), pp , [10] Ramesh V., Subbaah P., Preemptve routng for moble Ad-hoc networks, Proceedngs of Internatonal Conference on Sustanable nergy and Intellgent Systems (SISCON 2011), pp , [11] Yang Qn, Wen Y.Y., Ang H.Y., Choon m Gwee, A routng protocol wth energy and traffc balance awareness n wreless ad hoc networks, Proceedngs of th Internatonal Conference on Informaton, Communcatons & Sgnal Processng, pp.1-5, [12] Yao-guo Wang, Jn u, Improvng TCP Performance of Moble Ad hoc Networks by ack-up Mult-path Routng, Journal of Convergence Informaton Technology, vol. 7, no. 23, pp , [13] Ru Yang, Yng Song, Gu Chao, ao-ln Sun, nergy ntropy-aware Multpath Routng Algorthm n MANT, Internatonal Journal of Advancements n Computng Technology, vol. 4, no. 15, pp , ACADMY PUISHR